Wide range turbine governing arrangement



March 2, 1943. R. J. CAUGH'EY 2,312,958

WIDE RANGE TURBINE GOVERNING ARRANGEMENT 'Filed Oct 25, 1939 90550 IGHJPEEb I TUBE/IVE SHAFT Inventor: Reed J. caughey.

b\ W444? :3 His Attorney.

Paentedo 2 Reed 3. Caughey, Schenectady; N. Y., assignor to General NewYork Electric Company, a corporation of Application mm 2:, 1m, Seth] No.301,220 3 Claims. (cl; 264-3) The present invention relates to speedgoverning mechanisms for controlling prime movers. especially elasticfluid turbines having inlet valve means to be positioned in response tospeed changes, Such mechanisms usually include a speed responsive devicedriven or operated from the prime mover shaft and connected totheelement or elements to be controlled through the intermediary of ahydraulic motor and a relay. Difllculty is experienced whenever accuratecontrol of speed is required over a wide range,

particularlyif the speed responsive device is in the form of acentrifugal type governor. Such centrifugal governors permit accuratecontrol within a speed range of the order of 1:5, for example, where theprime mover speed varies within a speed range of from 440 to 2200 R. P.M. Beyond such speed range as, for example, of

i the order of 1:10, the ordinary centrifugal type of flyball governordoes not give accurate control because the power of the governor, whichvaries as the square of the speed, becomes insuflicient to attainsensitive regulation.-

It is an object of my invention to provide a new and improved controlmechanism for a prime mover whereby accurate speed control may beobtained within an extremely wide range of speed change. I

It is a further object of my invention to provide a new and improvedelastic fluid turbine governing arrangement and adjusting means ofelastic fluid to the turbine through the upper portion of the totalspeed range. the two governors being connected together so that thespeed control is automatically transferred from one to the other in asmooth and even manner. Control means are provided in the linkage systembetween the governors and the valve operating apparatus whereby thegoverning mechanism may be adjusted to maintain the speed of the elasticfluid turbine at any predetermined constantvalue within the range ofeither governor. I

For a considerationof what I believe to be novel and my invention,attention is directed to the following description and the claimsappended thereto taken in'connection with the accompanying drawing.

The single figure of the drawing is a schematic illustration of agovernor control mechanism for a prime mover in accordance with one formof my invention.

The prime mover in the present instance is shown as an elastic fluidturbine ll having an inlet valve II for controlling the flow of elasticfluid thereto. Arranged 1n the elastic fluid supply conduit l2 ahead ofthe control valve II is a stop valve i3 of any suitable type well knownin the art which may be controlled by operating means connected" to thestem ll thereof. The control valve it is provided with a stem lithe 1upper end of which is connected to the operating therefor wherebyaccurate speed control maybe obtained for any predetermined settingwithin an extremely wide range of speed change.

A still further object of the invention provide a new and improved primemover speed istobar I! pivoted at oneend to a stationary part l3. Theoperating bar It isbiased in the counter-clockwise direction, and hencethe control valve H to the closed position, by means of the suitablyarranged spring It. The left end of the control mechanism embodying aplurality of weed responsive devices sensitive to different speed rangeswhich may be adjusted sequentially to assume controlof the prime moverin the order of their ranges of sensitivity. 1

And a further object of the invention is to provide a new and improvedprime mover speed control mechanism embodying a plurality of speedresponsive devices arranged in such a cooperative manner whereby smoothand accurate control of the prime mover speed may be operating bar isprovided with a roller 2! which is adapted to be engaged by a liftingcam 22. The cam is driven through gear 23 and the cooperating rack bar24 by the hydraulic operating motor 25, piston 28 of the motor being'connected to the rack bar by stem 21. The supply of .operating fluid tothe hydraulic motor'is controlled by a suitable pilot valve 23 inaccordobtained for any predetermined speed within a a range greater thanthe operative limits of any one of such devices.

In the illustrated embodiment of my invention a pair of similar speedgovernors are provided,

one for controlling the admission of elastic fluid to the turbine duringthe lower portion of the once with impulses transmitted to. the stem ina manner well known in the art. The pilot valve stem 23 is plvotallyconnected to an intermediate point of a floating lever 3i. one end ofwhich lever is connected to the motor stem 21 and the other end to thestem 32 of the speed relay servo motor 33. The supply of operating fluidto the motor 33 is controlled by. the speed relay pilot valve 34, thestem 33 f which is connected for adjustment by the ating lever 33.

total speed range, the other controlling the now 58 One end of thefloating lever 33 is pivotally conthrough its full stroke.

that a full stroke movement of the relay motor speed responsive devices45 and 46, illustratedas being of the centrifugal or flyball typegovernors, the devices being responsive to continuous and substantiallynon-overlapping ranges of prime mover speed. One of these, for example,the device 45, i a low range speed governor so designed and adjustedthat its weights start to move outwardly at about 12 to per cent ofnormal prime mover speed, and reach their outermost positionatapproximately 50 per cent of normal prime mover speed. The secondgovernor 446 is so designed and adjusted that its weights begin to moveoutwardly just as the weight of the low range speed governors reachtheir outer limit and have an operating range of from 50 toapproximately 185 per cent of normal prime mover speed. The twogovernors 45 and 46 may be similar devices and may be driven from theprime mover shaft with diflerent gear ratios so that the low rangegovernor 45 will be operated at the same speed when the turbine isoperating at half speed as the high speed range governor 46 operateswhen the turbine is running at full speed. The governor 45 is connectedby link 441 to a beam 48 which is pivotally supported as at 49 to astationary part. The free end of the beam 48 is connected by link 5| toone end of the .floating lever 52. The governor 46 is connected by link55 to the beam 56 which is pivotally supported as at 51 to a stationarypart, the, free end of the beam 56 bein connected by link 59 to theother end of the floating lever 52. An intermediate point of the lever52 is connected by link 6| to the right end of lever 62, the left end ofwhich lever is pivotally connected to the adjustable sleeve 63. Thelever 62, is pivotally connected intermediate its ends by link 64 to thefloating lever part 65,

thepa'rt 65 being pivotally connected as at 66 to the floating lever 36and is normally biased for movement with the lever 36 by means of theiterconnecting spring 61. By the leverage arrangement as indicated onlya small increment of total governor travel is required to cause movementof the piston of speed relay motor 33 It is to be understood 33 willefiect through the pilot valve 28 a full stroke movement of the controlvalve operatin servo motor 25 and hence, also cause movement or thecontrol valve II throughout its full stroke.

For selectively determining the particular speed of the prime moverwhich is to be maintained by the governor, a hand lever 1| is providedpivotally mounted as at 12 and connected by link 13, b'ellcrank 14, andlink 15 to the sleeve 63 which is slidably arranged on the guide rod 16between stops 11 and 18. For minimum speed the sleeve 63 is adjustedagainst the lower stop 18 andlfor maximum speed against the upper stop11, while for intermediate speeds the sleeve 63 system may be adjustedwhereby the speed relay will be controlled with any selected portion ofthe governor stroke.

An additional control mechanism is provided for the relay operatinglever 36 whereby the main valve II may be actuated to closed "and openedpositions independently of the governor devices. By this mechanism, theprime mover is started up from standstill and during normal operation,the prime mover control is taken over automatically by the governors asthe speed thereof approaches that for which the governors are set.

Emergency tripping means are associated with this control mechanismwhereby the main valve is actuated to the closed condition upon anexcess prime mover speed. This control mechanism comprises a hand wheel8| rotatably mounted within a stationary part 82 and provided with aslotted sleeve 83 for cooperatively receiving an end of thelongitudinally movable screw 84. The end of the screw is provided with apin 85 projecting into the slot of the sleeve so that the screw will berotated by operation of the hand wheel. Cooperatively threaded upon thescrew is a sleeve 86 which sleeve is adapted to be restrained againstrotational movement with the screw 84 by a lever 81 pivotally connectedthereto at 88. The upper end of the lever 81 is connected by the link 89to a stationary part 9| while the lower end of the lever 81 is normallyrestrained by an emergency trip latch 82 which is pivoted to astationary part 93. The latch is pivotally connected at 94 to anoperating plunger 95, biased downwardly by spring 96, the lower end ofwhich plunger rests upon a stop portion 91 of a releasing trigger 86.

The trigger 98 is adaptedto be engaged at a predetermined excess primemover speed by a governor device 99 of a well known form imbedded withinthe prime mover shaft I8I. For resetting the emergency tripping device,the latch 92 is provided with an arm I82, the end of which extendsupwardly adjacent the screw 84 and is adapted to be engaged and reset bythe end of the sleeve 86 as it is moved to the extreme left along thescrew. The outer end of the screw'84 is pivotally connected at I 83 toone arm of a bellcrank I84 which bellcrank is pivoted upon a stationarysupport I85. The other bellcrank arm is connected to a stem i86 whichextends through a cooperating opening in the end of the floating lever36. The end of the stem I86 is provided with a stop I 81 for positioningthe floating lever 36 in accordance with the condition of adjustment ofthe hand wheel 8|. The screw 84 is biased toward the right by a suitablyarranged compression spring I88.

The operation of the control mechanism will now be described.Considering that the prime mover I8 is at standstill, the apparatus willbe substantially in the relative condition of adjustment as illustrated.The control valve II will be in the fully opened position due to thedeenergized condition of the governors '45 and 46 while the supply ofoperating fluid to the prime mover will be cut ofl. due to the closedcondition of the stop valve I3. The hand wheel 8| will first be rotatedin the clockwise direction whereupon the screw 84 will be moved to theright through the sleeve 86 under the force of the compression springI88. The bellcrank I84 will be rotated in the clockwise direction andthe stop I81 engaging with the floating lever 36 will rotate it in thecounterclockwise direction against the force of the spring 61. The relaypilot valve stem 35 will aeiaess be moved downwardly. so as to admitoperating fluid to the upper surface of the piston of the speed relayservo motor 88 causing it to move downwardly to its lowermost position.Lever Id will be rotated in the counterclockwise direction, and theright end of the lever 38 will be lifted to reclose the pilot valve 34.The stem 29 of the main pilot valve 28 will also be forced downwardly,so as to admit operating fluid to the lower surface of the piston of themain servo motor 25, whereupon the stem 21 will be forced upwardly. Thecam 22 will be rotated in the clockwise direction, thereby allowing thecontrol valve II to be moved to the fully closed position under theforce of the biasing spring I9. Further movement of the hand wheel 8! inthe clockwise direction after the closure of the control valve II willcause the sleeve 86 to travel to the left along the screw 84. The end ofthe sleeve 86 will engage with the latch arm I02 to effect the resettingof the emergency trip mech anism in the event that it had beenpreviously tripped, or if not, to'merely check that the trip mechanismis in the set condition. The stop valve I 3 may now be opened by itsoperating means. The control valve ii may be moved slowly in the openingdirection for admitting steam to the turbine by rotating the hand wheel8| in the counterclockwise direction. Upon such rotation the sleeve 86will first advance along the screw 84 toward the right until the lowrend of the lever 81 engages with the stop on the latch arm 92. Furthercounterclockwise rotation of the hand wheel BI and screw 84 causes thescrew to move to the left against spring I08, thereby rotating thebellcrank I04 in the counterclockwise direction. As stem I06 movesupwardly, the end ofthe floating lever'36 will follow stop Iii! underthe force of the tensioned spring 61. This movement of the floatinglever 36 will result in an upward movement of the pilot valve stem 35 toadmit operating fluid to the lower surface of the piston of the speedrelay motor 33. The

stem 29 of the main pilot valve 28 will be moved upwardly so as to admitoperating fluid to the upper surface of the piston 26 of the main servomotor 25. As the stem 21 and rack bar 24 move downwardly, the cam 22will be rotated in the counterclockwise direction so as to move thecontrol valve II slightly to the opened position corresponding to theadjustment of the hand wheel 8|. I

At about 12 to 15 per cent normal speed of the prime mover, the lever llbeing in the low speed position, the floating lever 36 will engage withthe lever 65 and the low-range speed governor 45 will assume thecontrol. of the machine. The hand wheel 8i may then be further rotatedtov its extreme position so as to move the stop I01 beyond the range ofnormal movement of the floating lever 38.

In the position indicated in the drawing the hand lever II is set forthe minimum speed condition holding sleeve 63 against the lower stop 18.At this condition of adjustment the low speed-range governor 45 willcome into operation to maintain a corresponding speed of the primemover. Any tendency of the prime mover to race beyond this speed willresult in an outward movement of the weights of the governor 45, adownward movement of the stems 6|, 64, and a counterclockwise movementof the floating lever 35 which, as described above, effects a closingmovement of the control valve II.

By movement of the handle of control lever their outer end positions.

II to the left, the sleeve ii! is raised upwardly upon the rod ii,thereby effecting an increase of the prime mover speed by a movement ofthe stem 84 in the upward direction. Simultaneously the governor 46 willeffect a corresponding movement of the link 8! in the downwarddirectlon'in accordance with the increase of turbine speed. The governorwill thereupon maintain the particular speed for which lever II is set.Thus it will be noted that upon movement of the control lever H to anypredetermined position, a corresponding adjustment of the speedgovernors is obtained. When the lever'H is ad- .iusted to such a primemover speed position that the low speed range governor 45 moves to itsfully opened position, the weights of the high speed range governor 48will begin to move outwardly to assume the control of the prime mover.During operation of the high speed governor the weights of the low speedgovernor remain in Outward movement of the fly-weights of the governor4i and the resultant counterclockwise movement of the beam 56 will beaccompanied by a downward movement of the link 59 which through thefloating lever 52 will effect a downward movement of the stem 8| whichin turn effects the adjustment of the control'valve II in a mannersimilar to the described operation for the low speed range governor l5.

It will be noted that the hand wheel Bl' may be utilized as a load limitcontrol means for the prime mover as well as for a starting control.

.As stated, during the normal running operation of the turbine, the handwheel is turned until the stop Illl is in its uppermost position andbeyond the limits of movement of the end of the floating lever 36. Byrotating the hand wheel in the reverse direction a predetermined amount,the left end of the lever 38 may be pulled down to any desired positionwhich will definitely limit the opening movement of-the' control valve II. ,Any effort exerted by the governors 45 or 48 to open the controlvalve further will merely result in the splitting of the lever '5 fromthe floating'lever 36 against the tension 7 of spring 81.

Summarizing, a governing system according to my invention comprises aplurality of devices responsive to consecutive non-overlapping ranges ofan operating condition such as the speed of a machine to be controlled.An element of such machine to be controlled in response to changes ofspeed orlike operating condition is connected to these devices by meansincluding a link and lever mechanism. The latter has a leveragesufficient to effect movement of the element through its entireoperating range in response to a. partial stroke of any of such devices.In case these devices are in the form of speed governors each governorhas an operating range or stroke consisting of a plurality ofconsecutive parts or partial strokes and the movement 'of any governorthrough any one of such consecutive parts effects with theaforementioned lever- 1. Governing system comprising a plurality ofdevices responsive to consecutive non-overlapping ranges of an operatingcondition of a machine, each device having as'troke consisting oi linkand lever mechanism having a leverage sumclent to elect movement, or theelement through its entire operating range in response to movement ofone of the governors through any one of several consecutive parts of itsoperating range. and means ior adjustingthe lever mechanism to eflectoperation of one 0! the governors within a predetermined part orits'operating range.

3. The combination with an element for controlling a machine of agoverning mechanism for the element comprising a speed governor foroperation at a low speedrange, another speed a plurality of partialstrokes, an element to he controlled in response to changes oi suchoperatingcondition, means iorconnecting thede vices to the element,saidv means including. a link and lever mechanism with a leverages'ufiicient to efiect movement of the element through its entireoperating range in response to a partial.

stroke of any one oi said devices, and means for adjusting the mechanismto sele t Op ration of one or the devices at a particular partialstroke.

2. Governing system comprising, a first and a second-speed governorhaving consecutive nonoverlapping speed ranges, an element forcontrolling a machine in response to speed changes, means including alink and lever mechanism ior connecting the governors to the element,the

governorior operation at a high speed range, a first lever, meanspivotal 1y connecting the govemors to separate 'points of the lever, anda mechanismincluding a second lever pivotally connected to the firstlever for moving the element in response to speed changes, aliulcrum forthe second lever, and means for adjusting the fulcrum, the leveragebetween each govemor and the. element being dimensioned to causemovement of the element through its full operating range within apart ofthe total movement of each governor and the last named means permittingselection of a plurality of parts of the total movement of each governorto move the element through its full operating range.

' REED J. CAUGHEY.

